Leaky Wave

This transmission structure, when designed properly, confines all the EM fields within the coax cable and allows the energy to be transferred, without much loss, over miles of cable length. This is because the EM field is trapped within the coax cable and all its energy is delivered to the user. The EM field is purposefully shielded from the environment and has no interaction with it. This is why cables can be buried under ground with minimal effect on performance.
But what if we somehow let the EM fields leak out of the coax cable? For example, we cut the end of the coax cable as shown in the video below. For sure it would ruin our TV reception and we wouldn’t get any internet information. However, it would allow the EM fields to interact with their surrounding environment. If we can control how the fields “leak out” and control which environment they interact with, we just might be able to make a useful sensor.